Hello I’m setting up a vehicle in Blender, so I need to assign armature to my object, and for axels and wheels I need to setup bone sticks , so to achieve that I must assign Look At constraints to axels stick bone to look at wheel stick bone. I see that some of users say that similar to Max Look At constraints are Blender Track to constraint, but Track To can be only assign to a armature in global but not to single bone, is thete any other solution for that in Blender.
Thanks
which version of blender are you using? at least in 2.59 there is a ‘track to’ constraint for bones. perhaps you’re getting confused, because blender has two constraint-tabs: one for object constraints and one for bone constraints (-> select your armature and change to pose mode [CTRL-TAB]).
First of all thanks for a help mikksu, I’m using Blender 2.59 . I see bone constrains but it’s only can apply to a object target, not to a Bone target , or I missing something up.
Thanks a lot,finaly solved 
I find Bone const.
OK there is a new a little bit problem
There is a three screenshots of the problem :
http://imageshack.us/g/101/sch1l.jpg/
I setup vertex groups, I setup parents to bones, I setup constrains to the bones, I setup armature to the mesh : CTRL+P , and every thing goes well, but the vertex gruops for the axels are not set properly to the axel bones ?
Please can some one suggest me what I need to do to setup my vertex gruops space orientation properly.
Thanks
Be best if you uploaded a .blend file, can’t really tell what is happening from the pics.
Randy
Here I was upload blend file :
http://www.mediafire.com/?5a6vr36sg2sfv2n
Got a few things wrong there. 1st, select the armature in object mode and look in the transforms panel in the 3d view (n-key to toggle panel view). The armature has a rotation and scale. Ctrl-A -> rotation and ctrl-A -> scale to clear those out. Those aren’t causing any problem now, but it might. In blender it’s best to always have the scale, location & rotation of the armature & mesh match.
2nd problem, you have 3 armature modifiers on the mesh. Select the mesh in object mode and look in the modifiers panel. Delete the last 2. This can happen when you parent a mesh to an armature, blender automatically adds an armature modifier to the mesh. If you clear the parenting of the mesh, blender doesn’t remove the armature modifier. Multiple armature modifiers will have deform the mesh multiple times. Say you have 2 armature modifiers and rotate a bone 45 degrees, the mesh will rotate 90 degrees.
3rd problem, and the biggest cause of your problems is your bones positions in rest pose. When vertex groups are assigned to a bone, they are assigned to that bone in it’s rest position. Select the armature and enter edit mode, now the bones are in rest pose and mesh is fine. Now select the ball at the root of K_P_D (root is big end of bone) shift-s -> cursor to selected. Select the ball at the tip of A_P_D (tip is small end) shift-s -> selected to cursor and the bone will snap to the root of A_P_D. Select the whole A_P_D bone by right clicking on the body of the bone and ctrl-N -> z-axis to reset the bone’s roll angle. Now that wheel should be fixed.
In blender, when rigging a mechanical object, I make the mesh separate mesh objects and just parent them to their bones. Select the mesh, shift select the armature, enter pose mode for armature and select control bone, then ctrl-p -> bone. Now the mesh object is attached to the bone, without needing to assign vertex groups.
Here’s a link to a video show mechanical rigging: http://www.vimeo.com/13347146
And here’s a link to a text version of the same project:http://issuu.com/blenderart_magazine…art_mag-29_eng
(look for the title ‘Rigging an Assembly Line Robot’)
Randy
Thanks Randy !